A forming method of a light-weight fan blade

Abstract

The application provides a forming method of a light fan blade, and the forming method comprises the following steps: (1) preparing an epoxy resin mixture, wherein the epoxy resin mixture comprises the following raw materials: a bisphenol A type liquid epoxy resin, a bisphenol A type solid epoxy resin, a silica modified ceramic powder, a fluorosilane modified four-needle zinc oxide whisker, a curing agent and a curing accelerator; a film is prepared by using the epoxy resin mixture, the film is compounded with a glass fiber cloth to obtain a prepreg; (2) cleaning a mold and applying a release agent; the prepreg is cut and laid; after the laying is completed, the mold is closed; (3) mold pressing forming; after curing and forming, cooling, taking out the mold and demolding. The forming method is simple and easy to operate, the finally prepared fan blade has the advantages of light weight, high strength and toughness and the like, and excellent comprehensive performance, and the overall quality of the fan can be effectively improved.

Description

Technical Field

[0001] This invention relates to the field of wind turbine blade technology, and specifically to a method for forming lightweight wind turbine blades. Background Technology

[0002] Fiber-reinforced resin composites, due to their high specific strength, high specific modulus, corrosion resistance, strong design flexibility, and ease of integral molding, have been widely used in various equipment materials. Furthermore, structural components of various shapes made from fiber-reinforced resin materials can replace traditional metal structural components, achieving the goal of weight reduction.

[0003] For wind turbines used in marine equipment, lightweight design is one of the key design requirements. Currently, wind turbine blades made of aluminum alloy or fiber-reinforced resin composites can meet the lightweight requirements, but fiber-reinforced resin composite wind turbine blades offer higher safety than aluminum alloy blades. Therefore, the fabrication of high-performance fiber-reinforced resin composite wind turbine blades plays a crucial role in improving the overall quality of wind turbines in marine equipment. Summary of the Invention

[0004] The purpose of this invention is to provide a method for forming lightweight wind turbine blades. The forming method is simple and easy to operate. The final wind turbine blades are lightweight while having high strength and toughness, and have excellent comprehensive performance, which can effectively improve the overall quality of the wind turbine.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A method for forming a lightweight wind turbine blade includes the following steps:

[0007] (1) Prepare epoxy resin mixture, wherein the epoxy resin mixture comprises the following raw materials: bisphenol A type liquid epoxy resin, bisphenol A type solid epoxy resin, silica modified ceramic powder, fluorosilane modified tetra-needle zinc oxide whiskers, curing agent, and curing accelerator.

[0008] An adhesive film is prepared using the epoxy resin mixture, and then the adhesive film is compounded with glass fiber cloth to prepare a prepreg for later use.

[0009] (2) Clean the mold and apply release agent; cut the prepreg and then lay the prepreg in the molding cavity of the mold according to the design sequence, ensuring that no air is trapped between each layer of prepreg; after laying, close the upper and lower molds.

[0010] (3) Transfer the mold after mold closing to the pressure equipment for molding; after the fan blades are cured and formed, reduce the temperature to below 50°C, release the pressure and take out the mold, and perform demolding to complete the forming of lightweight fan blades.

[0011] Preferably, in step (1), the epoxy resin mixture comprises the following raw materials in parts by weight: 50-65 parts of bisphenol A type liquid epoxy resin, 10-20 parts of bisphenol A type solid epoxy resin, 3-5 parts of silica-modified ceramic powder, 0.6-1.1 parts of fluorosilane-modified tetrane needle-shaped zinc oxide whiskers, 15-20 parts of curing agent, and 0.6-1 parts of curing accelerator;

[0012] The mass ratio of the adhesive film to the fiberglass cloth is (50-60):(40-50);

[0013] The glass fiber cloth is either unidirectional or biaxial glass fiber cloth.

[0014] Preferably, in step (1), the bisphenol A type liquid epoxy resin is one or more of epoxy resins E44, E51, and E54; the bisphenol A type solid epoxy resin is epoxy resin 0194.

[0015] The curing agent is composed of diethylaminopropylamine and polyamide 650 in a mass ratio of 1:(3-5); the curing accelerator is DMP-30.

[0016] The preparation method of the epoxy resin mixture includes the following steps: adding bisphenol A type solid epoxy resin to chloroform, stirring to completely dissolve the bisphenol A type solid epoxy resin, then sequentially adding bisphenol A type liquid epoxy resin, silica-modified ceramic powder, and silane-modified tetraneedle zinc oxide whiskers, stirring and mixing evenly, and then removing excess chloroform under vacuum conditions; then adding curing agent and curing accelerator, stirring thoroughly and evenly to obtain the epoxy resin mixture.

[0017] Preferably, in step (1), the preparation of the adhesive film using the epoxy resin mixture specifically includes the following steps: coating the epoxy resin mixture onto release paper to form an epoxy resin adhesive film, with a coating temperature of 55-60℃;

[0018] When the adhesive film is laminated with the fiberglass cloth, the lamination temperature is 65-70℃.

[0019] Preferably, in step (1), the silica-modified ceramic powder includes ceramic powder and silica coated on the ceramic powder; the ceramic powder is one or a combination of two of ZrB2 and ZrC; the particle size of the ceramic powder is 150-300 nm.

[0020] Preferably, the method for preparing the silica-modified ceramic powder includes the following steps:

[0021] Add 3-6 parts of ceramic powder, 2.5-5 parts of tetraethyl orthosilicate, and 0.5-1 parts of silane coupling agent KH-560 to 100 parts of anhydrous ethanol. After stirring and dispersing, slowly add water, and then slowly add a 10-15% hydrochloric acid solution to adjust the pH of the system to 4-5. Sonicate the mixture for 60-90 min, and then let it stand at 35-40℃ for 6-10 h. Filter out the treated ceramic powder. Then, vacuum dry the treated ceramic powder at 60-70℃, and then heat it to 500-550℃ at a heating rate of 10-15℃ / min under an argon atmosphere and calcine it for 2.5-3.5 h. Then cool it to room temperature under an argon atmosphere, and then grind and sieve it to prepare the silica-modified ceramic powder.

[0022] Preferably, in step (1), the preparation method of the fluorosilane-modified tetraneedle zinc oxide whiskers includes the following steps:

[0023] Prepare a 1.5-2% (w / w) fluorosilane ethanol solution and add it to a reaction vessel; immerse the tetrane-shaped zinc oxide whiskers in the fluorosilane ethanol solution, seal the reaction vessel, heat to 50-60℃ and hold for 3-5 hours, then cool to room temperature, remove and filter, wash with water and dry under a nitrogen atmosphere to obtain the fluorosilane-modified tetrane-shaped zinc oxide whiskers.

[0024] Preferably, the fluorosilane is one or a combination of two of tridecafluorooctyltriethoxysilane and heptadecafluorodecyltrimethoxysilane.

[0025] Preferably, in step (2), when laying the prepreg, after laying 5-8 layers of prepreg, vacuum pre-compression is performed, with a vacuum degree not lower than -0.07MPa and a vacuum time of 6-10min.

[0026] Preferably, in step (3), during the molding process, the temperature is first raised to 90-95℃ at a heating rate of 2-3.5℃ / min and held for 1 hour, then raised to 125-130℃ at a heating rate of 1-2℃ / min and held for 2 hours, then raised to 155-160℃ at a heating rate of 0.5-1℃ / min and held for 1.5 hours. The pressure during the molding process is 2-3 MPa.

[0027] The beneficial effects of this invention are:

[0028] 1. The method for forming wind turbine blades of the present invention uses glass fiber reinforced epoxy resin prepreg to prepare wind turbine blades, which can make wind turbine blades lightweight, and the overall forming method is simple, easy to operate, and convenient to manufacture.

[0029] 2. In the method for forming wind turbine blades of the present invention, silica-modified ceramic powder and silane-modified tetrane-shaped zinc oxide whiskers are used to composite-modify epoxy resin. The silica-modified ceramic powder includes ceramic powder (ZrB2, ZrC) and silica coating the ceramic powder. This ceramic powder has high strength and hardness, which can significantly enhance the strength, wear resistance, and other mechanical properties of the epoxy resin. The silica layer coating the ceramic powder has a certain roughness, which on the one hand allows for a tighter bond between the ceramic powder and the epoxy resin, thereby further improving the reinforcement effect; on the other hand, the outer silica layer can improve the aging resistance, corrosion resistance, and weather resistance of the wind turbine blades, thus extending the service life of the wind turbine blades.

[0030] The addition of fluorosilane-modified tetraneedle zinc oxide whiskers, with their surface modified by fluorosilane and rich in cover groups, significantly improves the compatibility between the tetraneedle zinc oxide whiskers and epoxy resin, resulting in better toughening and reinforcement. Furthermore, the tetraneedle zinc oxide whiskers possess a three-dimensional tetraneedle structure, providing completely isotropic reinforcement within the epoxy resin, thus enhancing its mechanical properties, heat resistance, and other properties.

[0031] 3. In the method for forming wind turbine blades of the present invention, while using silica-modified ceramic powder and fluorosilane-modified tetrane-shaped zinc oxide whiskers to modify epoxy resin, bisphenol A type liquid epoxy resin and bisphenol A type solid epoxy resin are selected as epoxy resin base material, and suitable curing agents and curing accelerators are selected. At the same time, the components are reasonably configured and combined with the optimized molding process, so that the final wind turbine blade has high strength and toughness while being lightweight, and has excellent comprehensive performance. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] Example 1:

[0034] A method for forming a lightweight wind turbine blade includes the following steps:

[0035] (1) Preparation of epoxy resin mixture. The preparation method of epoxy resin mixture includes the following steps: add epoxy resin 0194 to chloroform and stir to completely dissolve epoxy resin 0194. Then add epoxy resin E44, silica-modified ceramic powder and silane-modified tetrane needle-shaped zinc oxide whiskers in sequence. After stirring and mixing evenly, remove excess chloroform under vacuum conditions. Then add curing agent and DMP-30 and stir evenly to obtain epoxy resin mixture.

[0036] The epoxy resin mixture comprises the following raw materials in parts by weight: 58 parts epoxy resin E44, 20 parts epoxy resin 0194, 5 parts silica-modified ceramic powder, 0.9 parts fluorosilane-modified tetrane needle-like zinc oxide whiskers, 20 parts curing agent, and 0.6 parts DMP-30. The curing agent is composed of diethylaminopropylamine and polyamide 650 in a mass ratio of 1:5.

[0037] The epoxy resin mixture is then coated onto release paper to form an epoxy resin film at a coating temperature of 60°C. The film is then laminated with unidirectional glass fiber fabric at a lamination temperature of 70°C to prepare a prepreg for later use. The mass ratio of the film to the unidirectional glass fiber fabric is 60:40.

[0038] (2) Clean the mold and apply release agent; cut the prepreg and then lay the prepreg in the molding cavity of the mold according to the design sequence. No air should be trapped between each layer of prepreg; when laying the prepreg, vacuum pre-press after laying 7 layers of prepreg, the vacuum degree should not be lower than -0.07MPa and the vacuum time is 8min; after laying, close the upper mold and the lower mold.

[0039] (3) Transfer the mold after mold closing to the pressure equipment for compression molding. During the compression molding process, first heat up to 95°C at a heating rate of 3°C / min and hold for 1 hour, then heat up to 125°C at a heating rate of 2°C / min and hold for 2 hours, then heat up to 155°C at a heating rate of 1°C / min and hold for 1.5 hours. The pressure during the molding process is 3 MPa. After the fan blades have solidified and formed, reduce the temperature to below 50°C, release the pressure, remove the mold, and demold to complete the molding of the lightweight fan blades.

[0040] In step (1) of the above forming method, the silica-modified ceramic powder includes ZrC ceramic powder and silica coated on the ZrC ceramic powder; the particle size of the ZrC ceramic powder is 150-300 nm. The preparation method of silica-modified ceramic powder includes the following steps:

[0041] Add 6 parts of ZrC ceramic powder, 3 parts of tetraethyl orthosilicate, and 1 part of silane coupling agent KH-560 to 100 parts of anhydrous ethanol. After stirring and dispersing, slowly add water, and then slowly add 15% hydrochloric acid solution to adjust the pH of the system to 5. Sonicate the mixture for 90 min, and then let it stand at 35℃ for 10 h. Filter out the treated ceramic powder. Then, vacuum dry the treated ceramic powder at 65℃, and then heat it to 520℃ at a heating rate of 15℃ / min under an argon atmosphere and calcine it for 3 h. Then, cool it to room temperature under an argon atmosphere, and then grind and sieve it to prepare silica-modified ceramic powder.

[0042] The preparation method of the above-mentioned fluorosilane-modified tetrane needle-like zinc oxide whiskers includes the following steps:

[0043] Prepare a 2% (w / w) heptadecafluorodecyltrimethoxysilane ethanol solution and add it to a reaction vessel; immerse tetraneedle zinc oxide whiskers in the heptadecafluorodecyltrimethoxysilane ethanol solution, seal the reaction vessel, heat to 60°C and hold for 3 hours, then cool to room temperature, remove and filter, wash with water and dry under a nitrogen atmosphere to obtain fluorosilane-modified tetraneedle zinc oxide whiskers.

[0044] Example 2:

[0045] A method for forming a lightweight wind turbine blade includes the following steps:

[0046] (1) Preparation of epoxy resin mixture. The preparation method of epoxy resin mixture includes the following steps: add epoxy resin 0194 to chloroform and stir to completely dissolve epoxy resin 0194. Then add epoxy resin E44, silica-modified ceramic powder and silane-modified tetrane needle-shaped zinc oxide whiskers in sequence. After stirring and mixing evenly, remove excess chloroform under vacuum conditions. Then add curing agent and DMP-30 and stir evenly to obtain epoxy resin mixture.

[0047] The epoxy resin mixture comprises the following raw materials in parts by weight: 65 parts epoxy resin E44, 13 parts epoxy resin 0194, 4 parts silica-modified ceramic powder, 1.1 parts fluorosilane-modified tetrane-needle zinc oxide whiskers, 15 parts curing agent, and 8 parts DMP-300. The curing agent is composed of diethylaminopropylamine and polyamide 650 in a mass ratio of 1:3.

[0048] The epoxy resin mixture was then coated onto release paper to form an epoxy resin film at a coating temperature of 55°C. The film was then laminated with unidirectional glass fiber fabric at a lamination temperature of 65°C to prepare a prepreg for later use. The mass ratio of the film to the unidirectional glass fiber fabric was 56:44.

[0049] (2) Clean the mold and apply release agent; cut the prepreg and then lay the prepreg in the molding cavity of the mold according to the design sequence. No air should be trapped between each layer of prepreg; when laying the prepreg, vacuum pre-press after laying 5 layers of prepreg, the vacuum degree should not be lower than -0.07MPa and the vacuum time is 6min; after laying, close the upper mold and the lower mold.

[0050] (3) Transfer the mold after mold closing to the pressure equipment for compression molding. During the compression molding process, first heat up to 90°C at a heating rate of 2°C / min and hold for 1 hour, then heat up to 130°C at a heating rate of 2°C / min and hold for 2 hours, then heat up to 160°C at a heating rate of 0.8°C / min and hold for 1.5 hours. The pressure during the molding process is 2.5 MPa. After the fan blades have solidified and formed, reduce the temperature to below 50°C, release the pressure, remove the mold, and demold to complete the molding of the lightweight fan blades.

[0051] In step (1) of the above forming method, the silica-modified ceramic powder includes ZrC ceramic powder and silica coated on the ZrC ceramic powder; the ceramic powder is one or a combination of ZrB2 and ZrC; the particle size of the ZrC ceramic powder is 150-300 nm. The preparation method of silica-modified ceramic powder includes the following steps:

[0052] Add 5 parts of ZrC ceramic powder, 4 parts of tetraethyl orthosilicate, and 0.5 parts of silane coupling agent KH-560 to 100 parts of anhydrous ethanol. After stirring and dispersing, slowly add water, and then slowly add 15% hydrochloric acid solution to adjust the pH of the system to 4. Sonicate the mixture for 80 min, and then let it stand at 35℃ for 10 h. Filter out the treated ceramic powder. Then, vacuum dry the treated ceramic powder at 70℃, and then heat it to 550℃ at a heating rate of 12℃ / min under an argon atmosphere and calcine it for 2.5 h. Then cool it to room temperature under an argon atmosphere, and then grind and sieve it to prepare silica-modified ceramic powder.

[0053] The preparation method of the above-mentioned fluorosilane-modified tetrane needle-like zinc oxide whiskers includes the following steps:

[0054] A 2% (w / w) solution of tridecafluorooctyltriethoxysilane in ethanol was prepared and added to a reaction vessel. Tetraneous zinc oxide whiskers were immersed in the solution, the reaction vessel was sealed, and the temperature was raised to 55°C and held for 4 hours. The mixture was then cooled to room temperature, removed, filtered, washed with water, and dried under a nitrogen atmosphere to obtain fluorosilane-modified tetraneous zinc oxide whiskers.

[0055] Example 3:

[0056] A method for forming a lightweight wind turbine blade includes the following steps:

[0057] (1) Preparation of epoxy resin mixture. The preparation method of epoxy resin mixture includes the following steps: add epoxy resin 0194 to chloroform and stir to completely dissolve epoxy resin 0194. Then add epoxy resin E44, silica-modified ceramic powder and silane-modified tetrane needle-shaped zinc oxide whiskers in sequence. After stirring and mixing evenly, remove excess chloroform under vacuum conditions. Then add curing agent and DMP-30 and stir evenly to obtain epoxy resin mixture.

[0058] The epoxy resin mixture comprises the following raw materials in parts by weight: 50 parts epoxy resin E44, 10 parts epoxy resin 0194, 3 parts silica-modified ceramic powder, 0.6 parts fluorosilane-modified tetrane needle-like zinc oxide whiskers, 18 parts curing agent, and 1 part DMP-30. The curing agent is composed of diethylaminopropylamine and polyamide 650 in a mass ratio of 1:3.5.

[0059] The epoxy resin mixture is then coated onto release paper to form an epoxy resin film at a coating temperature of 58°C. The film is then laminated with unidirectional glass fiber fabric at a lamination temperature of 70°C to prepare a prepreg for later use. The mass ratio of the film to the unidirectional glass fiber fabric is 50:50.

[0060] (2) Clean the mold and apply release agent; cut the prepreg and then lay the prepreg in the molding cavity of the mold according to the design sequence. No air should be trapped between each layer of prepreg; when laying the prepreg, after laying 8 layers of prepreg, vacuum pre-pressing is performed. The vacuum degree is not lower than -0.07MPa and the vacuuming time is 10min; after laying, the upper mold and the lower mold are closed.

[0061] (3) Transfer the mold after mold closing to the pressure equipment for compression molding. During the compression molding process, first heat up to 95℃ at a heating rate of 3.5℃ / min and hold for 1 hour, then heat up to 125℃ at a heating rate of 2℃ / min and hold for 2 hours, then heat up to 155℃ at a heating rate of 0.5℃ / min and hold for 1.5 hours. The pressure during the molding process is 2 MPa. After the fan blades are solidified and molded, the temperature is reduced to below 50℃, the pressure is released and the mold is removed. The mold is then demolded to complete the molding of the lightweight fan blades.

[0062] In step (1) of the above forming method, the silica-modified ceramic powder includes ZrB2 ceramic powder and silica coated on the ZrB2 ceramic powder; the particle size of the ZrB2 ceramic powder is 150-300 nm. The preparation method of silica-modified ceramic powder includes the following steps:

[0063] Add 3 parts of ZrB2 ceramic powder, 5 parts of tetraethyl orthosilicate, and 0.8 parts of silane coupling agent KH-560 to 100 parts of anhydrous ethanol. After stirring and dispersing, slowly add water, and then slowly add 10% hydrochloric acid solution to adjust the pH of the system to 5. Sonicate the mixture for 60 min, and then let it stand at 40℃ for 6 h. Filter out the treated ceramic powder. Then, vacuum dry the treated ceramic powder at 60℃, and then heat it to 500℃ at a heating rate of 10℃ / min under an argon atmosphere and calcine it for 3.5 h. Then cool it to room temperature under an argon atmosphere, and then grind and sieve it to prepare silica-modified ceramic powder.

[0064] The preparation method of the above-mentioned fluorosilane-modified tetrane needle-like zinc oxide whiskers includes the following steps:

[0065] A 1.5% (w / w) solution of tridecafluorooctyltriethoxysilane in ethanol was prepared and added to a reaction vessel. Tetrane needle-shaped zinc oxide whiskers were immersed in the solution, the reaction vessel was sealed, and the temperature was raised to 50°C and held for 5 hours. The mixture was then cooled to room temperature, removed, filtered, washed with water, and dried under a nitrogen atmosphere to obtain fluorosilane-modified tetrane needle-shaped zinc oxide whiskers.

[0066] Example 4:

[0067] A method for forming a lightweight wind turbine blade includes the following steps:

[0068] (1) Preparation of epoxy resin mixture. The preparation method of epoxy resin mixture includes the following steps: add epoxy resin 0194 to chloroform and stir to completely dissolve epoxy resin 0194. Then add epoxy resin E44, silica-modified ceramic powder and silane-modified tetrane needle-shaped zinc oxide whiskers in sequence. After stirring and mixing evenly, remove excess chloroform under vacuum conditions. Then add curing agent and DMP-30 and stir evenly to obtain epoxy resin mixture.

[0069] The epoxy resin mixture comprises the following raw materials in parts by weight: 57 parts epoxy resin E44, 15 parts epoxy resin 0194, 3.5 parts silica-modified ceramic powder, 0.8 parts fluorosilane-modified tetraneedle zinc oxide whiskers, 17 parts curing agent, and 0.7 parts DMP-30. The silica-modified ceramic powder and fluorosilane-modified tetraneedle zinc oxide whiskers were prepared by the method described in Example 1; the curing agent is composed of diethylaminopropylamine and polyamide 650 in a mass ratio of 1:5.

[0070] The epoxy resin mixture was then coated onto release paper to form an epoxy resin film at a coating temperature of 60°C. The film was then laminated with unidirectional glass fiber fabric at a lamination temperature of 67°C to prepare a prepreg for later use. The mass ratio of the film to the unidirectional glass fiber fabric was 51:49.

[0071] (2) Clean the mold and apply release agent; cut the prepreg and then lay the prepreg in the molding cavity of the mold according to the design sequence. No air should be trapped between each layer of prepreg; when laying the prepreg, vacuum pre-press after laying 6 layers of prepreg, the vacuum degree should not be lower than -0.07MPa and the vacuum time is 7min; after laying, close the upper mold and the lower mold.

[0072] (3) Transfer the mold after mold closing to the pressure equipment for compression molding. During the compression molding process, first heat up to 93℃ at a heating rate of 3℃ / min and hold for 1h, then heat up to 130℃ at a heating rate of 2℃ / min and hold for 2h, then heat up to 160℃ at a heating rate of 0.8℃ / min and hold for 1.5h. The pressure during the molding process is 2.5Mpa. After the fan blades are solidified and molded, the temperature is reduced to below 50℃, the pressure is released and the mold is removed, and demolding is performed to complete the molding of the lightweight fan blades.

[0073] Example 5:

[0074] A method for forming a lightweight wind turbine blade includes the following steps:

[0075] (1) Preparation of epoxy resin mixture. The preparation method of epoxy resin mixture includes the following steps: add epoxy resin 0194 to chloroform and stir to completely dissolve epoxy resin 0194. Then add epoxy resin E44, silica-modified ceramic powder and silane-modified tetrane needle-shaped zinc oxide whiskers in sequence. After stirring and mixing evenly, remove excess chloroform under vacuum conditions. Then add curing agent and DMP-30 and stir evenly to obtain epoxy resin mixture.

[0076] The epoxy resin mixture comprises the following raw materials in parts by weight: 62 parts epoxy resin E44, 13 parts epoxy resin 0194, 4.5 parts silica-modified ceramic powder, 1 part fluorosilane-modified tetraneedle zinc oxide whiskers, 16 parts curing agent, and 6 parts DMP-300. The silica-modified ceramic powder and fluorosilane-modified tetraneedle zinc oxide whiskers were prepared by the method described in Example 2; the curing agent was composed of diethylaminopropylamine and polyamide 650 in a mass ratio of 1:3.5.

[0077] The epoxy resin mixture is then coated onto release paper to form an epoxy resin film at a coating temperature of 55°C. The film is then laminated with unidirectional glass fiber fabric at a lamination temperature of 70°C to prepare a prepreg for later use. The mass ratio of the film to the unidirectional glass fiber fabric is 55:45.

[0078] (2) Clean the mold and apply release agent; cut the prepreg and then lay the prepreg in the molding cavity of the mold according to the design sequence. No air should be trapped between each layer of prepreg; when laying the prepreg, vacuum pre-press after laying 7 layers of prepreg, the vacuum degree should not be lower than -0.07MPa and the vacuum time is 8min; after laying, close the upper mold and the lower mold.

[0079] (3) Transfer the mold after mold closing to the pressure equipment for compression molding. During the compression molding process, first heat up to 95℃ at a heating rate of 3.5℃ / min and hold for 1h, then heat up to 130℃ at a heating rate of 1.5℃ / min and hold for 2h, then heat up to 160℃ at a heating rate of 0.8℃ / min and hold for 1.5h. The pressure during the molding process is 2MPa. After the fan blades are solidified and molded, the temperature is reduced to below 50℃, the pressure is released and the mold is removed, and demolding is performed to complete the molding of the lightweight fan blades.

[0080] Comparative Example 1:

[0081] A method for molding lightweight wind turbine blades differs from Example 5 in that the raw materials in the epoxy resin mixture do not contain silica-modified ceramic powder. That is, the epoxy resin mixture includes the following raw materials in parts by weight: 62 parts of epoxy resin E44, 13 parts of epoxy resin 0194, 1 part of fluorosilane-modified tetrane needle-shaped zinc oxide whiskers, 16 parts of curing agent, and 0.6 parts of DMP-30.

[0082] Comparative Example 2:

[0083] A method for molding lightweight wind turbine blades differs from Example 5 in that the raw materials in the epoxy resin mixture do not contain fluorosilane-modified tetraneedle zinc oxide whiskers. That is, the epoxy resin mixture includes the following raw materials in parts by weight: 62 parts of epoxy resin E44, 13 parts of epoxy resin 0194, 4.5 parts of silica-modified ceramic powder, 16 parts of curing agent, and 0.6 parts of DMP-30.

[0084] Performance testing:

[0085] Following the molding methods described in Examples 1-5 and Comparative Examples 1-2, the materials were applied to prepare lightweight fiber-reinforced resin composite products for testing. Tensile strength, flexural strength, impact toughness, and salt spray resistance were then tested. The tensile strength test method followed GB / T 1447-2005 "Test Method for Tensile Properties of Fiber Reinforced Plastics"; the flexural strength test method followed GB / T 1449-2005 "Test Method for Flexural Properties of Fiber Reinforced Plastics"; the impact toughness test method followed GB / T 1451-2005 "Test Method for Simply Supported Beam Impact Toughness of Fiber Reinforced Plastics"; and the salt spray resistance test method followed GJB150.11A-2009 (96h) standard. Specific test results are shown in Table 1.

[0086] Table 1 Performance Test Results

[0087]

[0088] As shown in Table 1, the lightweight fiber-reinforced resin composite materials obtained by the molding methods in Examples 1-5 of this invention possess excellent mechanical properties, with good strength and toughness. Therefore, the resulting wind turbine blades also exhibit superior mechanical properties and excellent salt spray resistance, which is beneficial for improving the overall quality of wind turbines in marine equipment. A comparison between Example 5 and Comparative Examples 1-2 shows that when molding lightweight fiber-reinforced resin composite materials (e.g., wind turbine blades), using silica-modified ceramic powder or silane-modified tetraneedle zinc oxide whiskers to modify epoxy resin can significantly improve the mechanical properties of the resulting composite materials.

[0089] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method of forming a lightweight fan blade, comprising: Comprise the following steps: (1) Preparation of epoxy resin mixture, the epoxy resin mixture comprises the following raw materials by weight: liquid epoxy resin of bisphenol A type 50-65 parts, bisphenol A type solid epoxy resin 10-20 parts, silica modified ceramic powder 3-5 parts, fluorosilane modified four needle zinc oxide whisker 0.6-1.1 parts, curing agent 15-20 parts, curing accelerator 0.6-1 parts; The said epoxy resin film is prepared by using the said epoxy resin mixture, and the said epoxy resin film is compounded with glass fiber cloth to prepare prepreg for standby; The mass ratio of the said epoxy resin film and glass fiber cloth is (50-60):(40-50); The glass fiber cloth is glass fiber unidirectional cloth or glass fiber biaxial cloth; (2) Clean the mold and apply release agent; cut the prepreg, then lay the prepreg in the forming cavity of the mold according to the design sequence; after laying, close the upper and lower molds; (3) Transfer the closed mold to the pressure equipment for molding; after the fan blade is cured and formed, reduce the temperature to below 50 DEG C, unload the mold and demold, and complete the molding of the lightweight fan blade.

2. The method of claim 1, wherein In step (1), the liquid epoxy resin of bisphenol A type is one or more of epoxy resin E44, E51 and E54; the solid epoxy resin of bisphenol A type is epoxy resin 0194; The curing agent is composed of diethylaminopropylamine and polyamide 650 in a mass ratio of 1:(3-5); the curing accelerator is DMP-30; The preparation method of the epoxy resin mixture comprises the following steps: adding the solid epoxy resin of bisphenol A type into chloroform, stirring to dissolve the solid epoxy resin of bisphenol A type completely, then adding the liquid epoxy resin of bisphenol A type, silica modified ceramic powder and silane modified four needle zinc oxide whisker in sequence, stirring and mixing uniformly, then removing the excess chloroform under vacuum condition; then adding the curing agent and curing accelerator, stirring uniformly, and obtaining the epoxy resin mixture.

3. The method of forming a lightweight fan blade according to claim 1, wherein In step (1), the preparation of the epoxy resin film by using the epoxy resin mixture comprises the following steps: coating the epoxy resin mixture on release paper to form an epoxy resin film, and the coating temperature is 55-60 DEG C; When the epoxy resin film is compounded with glass fiber cloth, the compounding temperature is 65-70 DEG C.

4. The method of forming a lightweight fan blade according to claim 1, wherein In step (1), the silica modified ceramic powder comprises ceramic powder and silica coated on the ceramic powder; the ceramic powder is one or a combination of ZrB2 and ZrC; the particle size of the ceramic powder is 150-300 nm.

5. The method of forming a lightweight fan blade according to claim 1, wherein The preparation method of the silica modified ceramic powder comprises the following steps: To 100 parts of anhydrous ethanol, 3-6 parts of ceramic powder, 2.5-5 parts of tetraethyl orthosilicate, and 0.5-1 part of silane coupling agent KH-560 are added, and after stirring and dispersing, water is slowly added, and a hydrochloric acid solution with a mass fraction of 10-15% is slowly dripped to adjust the pH value of the system to 4-5, and then ultrasonic dispersion is performed for 60-90 min, and then the system is placed at 35-40℃ for 6-10 h, and the treated ceramic powder is filtered out; then the treated ceramic powder is vacuum dried at 60-70℃, and then heated to 500-550℃ at a heating rate of 10-15℃ / min under an argon atmosphere, and then heat treated for 2.5-3.5 h, and then cooled to room temperature under an argon atmosphere, and then ground and sieved to obtain the silica-modified ceramic powder.

6. The method of forming a lightweight fan blade according to claim 1, wherein In step (1), the preparation method of the fluorosilane-modified four-needle-shaped zinc oxide whisker comprises the following steps: A fluorosilane ethanol solution with a mass fraction of 1.5-2% is prepared and added to a reaction kettle; the four-needle-shaped zinc oxide whisker is immersed in the fluorosilane ethanol solution, the reaction kettle is closed, and then heated to 50-60℃ for 3-5 h, and then cooled to room temperature, taken out, filtered, washed with water, and dried under a nitrogen atmosphere to obtain the fluorosilane-modified four-needle-shaped zinc oxide whisker.

7. The method of forming a light-weight fan blade according to claim 1, wherein The fluorosilane is one or a combination of tridecafluorooctyltriethoxysilane and heptadecafluorodecyltrimethoxysilane.

8. The method of forming a lightweight fan blade according to claim 1, wherein In step (2), when laying up the prepreg, vacuum pre-pressing is performed after laying up 5-8 layers of prepreg, and the vacuum degree is not less than -0.07 MPa, and the vacuum time is 6-10 min.

9. The method of forming a lightweight fan blade of claim 1, wherein, In step (3), in the process of mold pressing, first, heating is performed at a heating rate of 2-3.5℃ / min to 90-95℃, and then held for 1 h, and then heating is performed at a heating rate of 1-2℃ / min to 125-130℃, and then held for 2 h, and then heating is performed at a heating rate of 0.5-1℃ / min to 155-160℃, and then held for 1.5 h, and the pressure during the molding process is 2-3 MPa.

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